Hibernate and PostgreSQL configuration using persistence.xml and EntityManager
In this tutorial I am going to show you how to use Hibernate with Entity Manager. It is based on my previous tutorial and it is an enhancement of this code. In previous tutorial I was using “hibernate-entitymanager” dependency, so there is no need to do any modifications in pom.xml now.
1. Create persistence.xml file in src/main/resources/META-INF directory. You can also remove hibernate.cfg.xml, but it is not mandatory.
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<persistence xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd" version="2.0"> <persistence-unit name="entityManager"> <provider>org.hibernate.ejb.HibernatePersistence</provider> <!-- Annotated entity classes --> <class>com.jvmhub.tutorial.entity.AppUser</class> <properties> <property name="hibernate.connection.url" value="jdbc:postgresql://localhost/jvmhubtutorial" /> <property name="hibernate.connection.driver_class" value="org.postgresql.Driver" /> <property name="hibernate.connection.username" value="user" /> <property name="hibernate.connection.password" value="password" /> <property name="hibernate.dialect" value="org.hibernate.dialect.PostgreSQLDialect" /> <property name="hibernate.hbm2ddl.auto" value="create-drop" /> </properties> </persistence-unit> </persistence> |
2. Modify AppTest class to be consistent with EntityManager usage.
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package com.jvmhub.tutorial; import javax.persistence.EntityManager; import javax.persistence.Persistence; import junit.framework.TestCase; import com.jvmhub.tutorial.entity.AppUser; /** * Unit test for simple App. */ public class AppTest extends TestCase { private EntityManager entityManager; public void testApp() { entityManager = Persistence.createEntityManagerFactory("entityManager") .createEntityManager(); entityManager.getTransaction().begin(); AppUser user = new AppUser("seconduser"); entityManager.persist(user); entityManager.getTransaction().commit(); entityManager.close(); } } |
3. After that all you should have directory structure like below:
4. Execute mvn test command in the project’s directory.
If everything is OK, you should have your second entry in the database persist by Hibernate!
Complete source code: https://github.com/jvmhub/Hibernate-and-PostgreSQL-configuration-using-persistence.xml-and-EntityManager